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In this study, the amount of prevented household waste in Kyoto city was quantified using three methods. Subsequently, the greenhouse gas (GHG) emission reduction by waste prevention was calculated in order to monitor the impact of waste prevention. The methods of quantification were "relative change from baseline year (a)," "absolute change from potential waste generation (b)," and "absolute amount of activities (c)." Method (a) was popular for measuring waste prevention, but method (b) was the original approach to determine the absolute amount of waste prevention by estimating the potential waste generation. Method (c) also provided the absolute value utilizing the information of activities. Methods (b) and (c) enable the evaluation of the waste prevention activities with a similar baseline for recycling. Methods (b) and (c) gave significantly higher GHG reductions than method (a) because of the difference in baseline between them. Therefore, setting a baseline is very important for evaluating waste prevention. In practice, when focusing on the monitoring of a specific policy or campaign, method (a) is an appropriate option. On the other hand, when comparing the total impact of waste prevention to that of recycling, methods (b) and (c) should be applied.

The purpose of this study was to quantify the life-cycle greenhouse gas (GHG) emissions reduction that could be achieved by replacement of fossil-derived materials with biodegradable, biomass-based materials for household plastic containers and packaging, considering a variety of their treatment options. The biomass-based materials were 100% polylactide or a combination of polybutylene succinate adipate and polylactide. A scenario analysis was conducted considering alternative recycling methods. Five scenarios were considered: two for existing fossil-derived materials (the current approach in Japan) and the three for biomass-based materials. Production and waste disposal of 1 m3 of plastic containers and packaging from households was defined as the functional unit. The results showed that replacement of fossil-derived materials with biomass-based materials could reduce life-cycle GHG emissions by 14–20%. Source separation and recycling should be promoted. When the separate collection ratio reached 100%, replacement with biomass-based materials could potentially reduce GHG emissions by 31.9%. Food containers are a priority for replacement, because they alone could reduce GHG emissions by 10%. A recycling system for biomass-based plastics must be carefully designed, considering aspects such as the transition period from fossil-derived plastics to biomass-based plastics.

Since end-of-life vehicles (ELVs) contain toxic substances, they have to be treated properly. The purpose of this study was to obtain useful information for ELV management from the viewpoint of toxicity. We focused on lead as a representative toxic substance contained in vehicles and investigated the dynamic substance flow of lead contained in ELVs and its content in automobile shredder residue (ASR). A population balance model was used to estimate the number of ELVs generated between FYs (fiscal year) 1990–2020, employing a Weibull distribution for the lifespan distribution. Sixteen lead-containing components of the vehicle were considered. It was estimated that the annual number of ELVs generated would be 2.9 million as of FY2020. The results implied that it is hard to remove Pb completely. This is because 5,000–11,000 t-Pb will still remain in vehicles in use in FY2020 even though most components in new model vehicles could be replaced by lead-free alternatives. As of FY2010, the substance flow showed that Pb contained in ELVs amounted to 4,600–5,700 t-Pb. Of this, 13.2–14.0 % was contained in ASR. The Pb content in ASR could be dramatically decreased by FY2020, but it will continue to contain 240–420 mg-Pb/kg if the treatment system is not improved.

Open dumping sites in Surabaya and Palembang, Indonesia, have been studied to investigate emissions of polychlorinated dibenzo-para-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs), as well as the resulting soil contamination that might be caused by open burning of municipal solid waste. The emission factors of the waste residue, accounting for the ratio of waste burned, have also been characterized. The concentrations of PCDD/Fs and DL-PCBs in soil from Palembang were 61–310 pg-TEQ/g (dry weight) and 6.3–32 pg-TEQ/g, respectively. In Surabaya, very low levels of PCDD/Fs and DL-PCBs, ranging from 0.075 to 0.098 and 0.00032 to 0.095 pg-TEQ/g, respectively, were observed in soil for an open dumping site that included a top cover layer of soil above the compacted waste. The large difference in concentrations can be explained by the fact that open burning of waste is the source of PCDD/Fs and DL-PCBs. The emission factors for the residue for PCDD/Fs ranged from 27 to 140 pg-TEQ/g, and a sensitivity analysis found that the maximum emission factor to the residue could be 5600 pg-TEQ/g. Our results indicate that emissions of PCDD/Fs can be controlled by modifying the open dumping process to one that involves depositing soil layers on top of the compacted waste.

A simplified life cycle assessment was conducted to estimate greenhouse gas (GHG) emissions and energy production from each component of biogenic waste treated in an open dumping site, and by composting, anaerobic digestion, and incineration employed with additional options. The impact of uncertainties and sensitivities of the parameters in the treatment methods were investigated. We conducted a sensitivity analysis to identify the most sensitive parameters, and we discussed the relationship between uncertainty and sensitivity. Our results revealed that the moisture content of food waste and the biomass-derived carbon and methane concentration of the landfill gas of biogenic waste subjected to open dumping are the most sensitive parameters across all the treatment methods. The net GHG emissions from food waste treated in an open dumping site ranged over ten times (0.30 − 3.67 Gg CO2 eq/Gg). In addition, by employing additional options for the open dumping site, including soil cover, a landfill gas collection system, shifting to a semi-aerobic condition, and energy conservation by using a gas engine, we found that the net GHG emissions could be reduced by 10, 27.9, 37.4 %, and up to 56.7 %, respectively. Shifting to a semi-aerobic system is the most effective method for reducing GHG emissions, followed by landfill gas collection.

本稿では, 自治体固有の影響や年度固有の影響を考慮したパネルデータ分析 (2001-2007) により, 産業廃棄物税 (以下, 産廃税) による全産業廃棄物および品目別 (廃プラスチック類, 汚泥, がれき類) の課税効果を推定した. 特に, 産廃税制度設計要因として徴税方法別の課税効果や焼却施設への課税効果について検証した. この結果, 特別徴収方式の産廃税導入により, 全産業廃棄物, 汚泥, がれき類に対する最終処分量の削減効果, ならびに全産業廃棄物, 廃プラスチック類, 汚泥に対する中間処理量の増加作用が推定された. また, 埋立処分と焼却に対して課税した場合, 埋立処分のみに課税した場合に比べて, 廃プラスチック類で4割, 汚泥で3割の中間処理量の削減効果があるが, がれき類ではその効果は表れないことが確認された. 品目別で課税効果に差が見られ, 廃棄物処理フローへの影響がそれぞれ異なることが確認された., In Japan, 27 prefectures have implemented an industrial waste tax system comprised of two taxation methods: payment by self-assessment, and payment by special collection. In this study, we estimate waste reduction and recycling effects resulting from the implementation of the industrial waste tax using panel data from 47 prefectures during the period 2001 to 2007. The study looked at the total amount of industrial waste being generated and the three categories of industrial waste (plastic waste, sludge, and debris). The paper also analyzes the impacts on waste flow caused by these two taxation methods and taxation on incineration facilities. First, results verified that the industrial waste tax using payment by special collection had a greater effect on waste reduction with regard to final disposal amounts for total industrial waste, sludge, and debris. Moreover, taxation increased the amount of intermediate treatment for total industrial waste, plastic waste, and sludge. Next, we calculated that taxation on incineration facilities would reduce the intermediate treatment amount of plastic waste by 40 percent and that of sludge by 30 percent. Finally, we confirmed that the effects of the industrial waste tax will vary across the different waste categories.

Reduce, reuse, and recycle (3R) policies form the basis of waste management and global warming countermeasures globally, so we conducted a comparative study of 3R and waste management policies in the European Union (EU), USA, Korea, Japan, China, and Vietnam. An international workshop for 3R and waste management policymakers was held in Kyoto, Japan, and a bibliographic survey was also conducted to collect data. 3R policies are clearly given priority in the hierarchy of waste management in every country studied. Thermal recovery, which includes power generation from waste heat and methane gas collected from organic waste, is also a priority; this is consistent with the increased use of countermeasures to reduce greenhouse gas (GHG) emissions. In the EU, waste management is characterized by practical and effective 3R policies through the development of realistic regulations and by the policymakers’ desire to simplify management systems. The policy ideal in China, however, is the development of a circular economy that targets reductions in the amount and hazardousness of waste. Limits on the number of final disposal sites, strategies for procuring resources, and GHG emission countermeasures are closely linked with 3R policies, and further development of 3R policies in parallel with such issues is expected.

国内都市部の一例として京都市を対象に，都市ごみ中のバイオマスである厨芥類および紙類の賦存量を推定した。厨芥類の発生量は22.2万ton-wet/年，紙類は22.3万ton-wet/年であり，ほぼ全量が焼却処理されている。これらを対象に利用システムの温室効果ガス (GHG) 削減効果およびエネルギー回収率を評価した結果，「バイオガス化 (高温乾式メタン発酵)＋ガスエンジン発電 (GE)」は既存の「直接燃焼＋蒸気発電」，「直接燃焼＋堆肥化」よりも有利であった。また，バイオガス発電時の廃熱を利用する超高温可溶化技術を組み込んだ可溶化システムでは，現状の乾式方式に対してエネルギー回収率およびGHG削減効果で27%の向上が見込まれた。さらに，バイオガスの燃料電池利用により，GE利用の最大1.7倍まで効果向上が期待された。国内温室効果ガスの削減に向けて都市ごみ中バイオマスの高度なエネルギー変換技術の普及が望まれる。

ビデオテープレコーダー，DVDビデオ，ビデオカメラ，デジタルカメラ，フラッシュメモリプレーヤー，HDDオーディオプレーヤー，ゲーム機器，携帯電話の8品目を対象に，日本における廃棄量および含有物質の潜在的な含有量の試算を行った。また，廃棄先・自治体におけるリサイクル実態について，アンケート調査を行った。廃棄量は年間約60,000tonと概算され，約0.4kg/(人・年) と，家電4品目6.7kg/(人・年) に比べては多くない結果であった。潜在的な資源量は金約4ton，パラジウム約3tonと資源密度が高かった。廃棄先は，携帯電話を除いては，自治体が50%以上を占める最大の排出先であった。約8割の自治体が，破砕処理後，リサイクルを行っている。その内訳は，鉄が約9割であり，レアメタルについてはほとんどリサイクルされていない。さらに，隠れたフローやe-wasteを含めた小型電気電子機器のリサイクル推進に向けた政策的な視点を整理した。

Atmospheric emissions of deca-brominated diphenyl ether (DBDE) in Japan were estimated based on the material flow of DBDE products and their emission factors. In 2002, the demand for DBDE in Japan was 2200 ton/year and the stock level was about 60 000 ton. The DBDE flow into the waste stream was estimated to be about 6000 ton/year and the flow out through second-hand product exports was more than 700 ton/year. Home appliance recycling facilities dismantle and crush domestic wastes containing about 600 ton of DBDE annually. Material recycling of crushed plastics is not commonly practiced as yet. Emission factors from plastics processing (2 × 10−9–1 × 10−7), textile processing (9 × 10−7), home appliance recycling (8 × 10−9–5 × 10−6), and waste incineration (1 × 10−7–2 × 10−6) were estimated using field measurement data. The DBDE emission rate through house dust during the service life of final products (2 × 10−7–9 × 10−7 per year) was estimated using the DBDE concentration in dust and the amount of dust in used televisions. Emission factors from previous studies were also used. The estimated total DBDE emission was 170–1800 kg/year. These results suggest the necessity of characterizing emissions during the service life of products, which is essential information for formulating an appropriate e-waste recycling strategy.

自動車用鉛バッテリーのリサイクル・廃棄フローモデルを作成し, インターネットアンケート調査から退蔵バッテリー残存率関数を定め, 静脈フローを推定した。補修用バッテリー販売時の廃バッテリー回収率は, ガソリンスタンド・整備業では10割に近く, カーショップで約8割, ホームセンターで約5割, 平均回収率は85%で, 約230万個/年が未回収と推定された。不要となった後も家庭内で保管 (退蔵) されるバッテリーのストック数は約500万個, 平均滞留年数は約2.2年と推定された。これらの結果と統計等を元に推定した2003年度の不要バッテリーのリサイクル率は, 精錬業で原料利用した国内再生率84%, 国内解体率87% (解体後に得られる巣鉛の輸出を含む) , 中古バッテリー輸出を含む国内回収率89%であった。残る11%は, 中古車上の車載輸出 (約5%) , 焼却・埋立, 不法投棄, 退蔵純増に至ると推定された。

バイオ資源・廃棄物等について, 各市町村の統計データを基に賦存量を推定し, 資源品目毎に1自治体あたりおよび1人あたり賦存量と人口規模との関係を整理した。農産系・林産系・畜産系バイオマスでは人口規模が小さいほど1人あたり量や累積賦存量 (一定の人口規模の自治体での総量) が多くなるのに対して, 廃棄物系バイオマスでは逆の傾向を示すことが明らかになった。また, 厨芥類を対象として, 燃料電池でのバイオガス利用を含む4つの処理シナリオを設定し, 人口規模小の地域 (農村部) および人口規模大の地域 (都市部) をモデルに温室効果ガスを評価項目としたケーススタディを行った。焼却や堆肥化と比較してメタン発酵によるバイオガス回収・発電利用はCO2排出量が少ないこと, 燃料電池はガスエンジンよりもCO2削減効果が大きいこと, 農村部と都市部の違いがシナリオの評価に影響することが示された。

低濃度PCB汚染油の処理対象基準濃度設定に資するため, 廃油処理に伴う作業者および周辺居住者のリスクを評価した。廃油中PCB濃度が50mg/kgのとき居住者の追加的曝露量推定値はPCB・ダイオキシン類のTDIの1/20以下であり, 作業環境のダイオキシン類濃度推定値は, 管理濃度2.5P9-TEQ/m3の1/100以下であった。また, 5mg/kg以下で作業者の体内負荷量最大値は個人差を考慮しない場合のNOAEL以下となった。処理対象外となる廃油の平均PCB濃度は, 処理基準が20mg/kgのとき4.8mg/kgと推定された。PCBの環境放出量は日本の現在の年間排出量の1%以下と推測された。

PCB廃棄物処理事業の費用効率性を既往対策 (廃棄物焼却炉ダイオキシン類対策事業) と比較した。比較には, 同一の環境運命・曝露モデルによって算出した摂取量削減量あたりのコストを用いた。対策コストは既報の値を用い, 摂取量削減量は既報の放出量削減量をモデルの入力として, 環境運命・曝露モデルによって推定した。評価期間は, 現世代にとっての費用効率性という視点から, 30年間とした。PCB処理事業による摂取量削減量の上限は, 大気放出削減時0.8g-TEQ, 水系放出削減時5.79-TEQ, 土壌放出削減時1.6g-TEQと推定され, 焼却炉対策事業での摂取量削減量は3.5～11g-TEQと推定された。また, 摂取量削減量あたりコストはPCB処理事業で0.27～1.9億円/mg-TEQ, 焼却炉対策で0.67～2.1億円/mg-TEQと同程度となった。PCB処理事業は焼却炉対策と同程度の費用効率性を有するといえる。

PCB廃棄物の保管継続と処理促進とのリスクを比較した。モニタリングデータとモデル推定値との比較より, 保管継続に伴うPCB放出量の上限は, 土壌排出でPCB不明・紛失量と同程度, 大気および水系排出でその1/10程度と推定された。Co-PCB個人曝露量は, 保管継続時の上限が数pg-TEQ/人/日であり, 処理促進時は処理施設周辺で0.1～0.7pg-TEQ/人/日, その他国内でさらに2～4オーダー低く推定された。人口を乗じた曝露総量では施設周辺以外の比率が高く, 国外も数割を占めた。地域別の個人曝露量および曝露総量の推定結果は, 局地的な効果と大局的な効果の双方を考慮することの必要性を示唆した。

今後大量に廃棄されると考えられる薬剤処理木材には, 各種化学物質が残存していると考えられる。廃木材リサイクリングルートにおけるそれらのヒト健康リスクを評価するため, 曝露ポイントとして, 廃木材の1) 切断作業, 2) 室内利用をあげ, 経気道・経口曝露ルートによるガス状・粒子状の重金属類 (Cr, Cu, As) , PCP (ペンタクロロフェノール) , PCDD/DFs (ダイオキシン類) 及びPAHs (多環芳香族炭化水素) の曝露解析を行った。その結果, 廃木材切断作業や室内利用に伴う経気道及び経口での化学物質曝露量が日常レベルを大きく上回るほか, 継続的な曝露がヒト健康へのリスクを発癌リスク10-4にまで高める可能性が示唆された。

家庭由来食品残渣の処理方式4種 (焼却, メタン発酵+残渣焼却, メタン発酵+残渣堆肥化, 堆肥化) を対象としてLCAを行った。環境影響領域として地球温暖化, 酸性化, 埋立地消費, 有害物質によるヒトへの健康影響をとりあげDistance to Target (DtT) 法による重み付け評価をした。有害物質としてはダイオキシン類および重金属類を取り上げ, 3種のMackayモデルを用いた特性化を試みた。メタン発酵を含むシナリオは含まないシナリオに比べ, 環境負荷を低減する傾向にあった。堆肥化は焼却処理に比べ温室効果ガス排出が多いが, DtT法による評価では埋立量削減の効果がこれを上回った。有害物質による影響は用いる特性化係数によって異なり, 定常モデルでは農地への重金属排出による影響がダイオキシン類の大気排出による影響より大きいと評価されたが, 100年間の影響を見る動的モデルでは, ダイオキシン類の大気排出が支配的な影響を持つと評価された。

Unit-charging programs known as pay-as-you-throw (PAYT) for municipal solid waste in Japan were surveyed. The number of municipalities that have implemented PAYT for combustible waste totaled 954 (30%) in 2003. The introduction of PAYT programs peaked in the early 1970s and again in the 1990s. PAYT has tended to be adopted by municipalities with small populations (less than 30,000). PAYT charging systems can be roughly divided into two groups: simple unit-pricing programs and two-tiered pricing programs. It is difficult to see the relationship between PAYT and waste reduction by simple inspection of the overall changes throughout Japan. Case studies of four municipalities showed that the implementation of PAYT programs reduced the amount of residual waste generated by 20% to 30%. In combination with other measures, especially the recycling of containers and packaging, PAYT programs can bring about a dramatic reduction in waste.

The Chinese Government ratified the Stockholm Convention on Persistent Organic Pollutants (POPs) on 25 June 2004. As a party to the Convention, China is preparing its National Implementation Plan (NIP), which must be finished and submitted to the Conference of the Parties before November 11, 2006. The emission inventory and strategy for reducing unintentionally formed products is a very complex and difficult part of the NIP. In this paper, we analyzed the potential sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in China and calculated their possible emissions. We included municipal solid waste incineration, hazardous and medical waste incineration, pulp bleaching, sodium pentachlorophenate production and usage, illegal electrical and electronic waste ("e-waste") recycling, and ferrous and non-ferrous metal production, and prepared a preliminary analysis of dioxin emissions in China. The results show that ferrous metal production (104.2-6648.3g TEQ), non-ferrous metal production (2.6-3389.8 g TEQ), and sodium pentachlorophenate production and usage (120-368.0 g TEQ) should be major potential sources of dioxins and furans. Moreover, municipal solid waste and hazardous and medical waste incineration (35.5 g TEQ) should also be considered high priority sources owing to a rapidly increasing incineration ratio anticipated for the near future.

End-of-life vehicles (ELV) have become a global concern as automobiles have become popular worldwide. An international workshop was held to gather data and to discuss 3R policies and ELV recycling systems, their background and present situation, outcomes of related policies and programs, the framework of recycling and waste management, and case studies on related topics in several countries and regions, as well as the essential points of the comparison. Legislative ELV recycling systems are established in the EU, Japan, Korea, and China, while in the US, ELV recycling is managed under existing laws on environmental protection. Since automobile shredding residue (ASR) has a high calorific value and ash content, and includes heavy metals as well as a mass of unclassified fine particles, recycling ASR is considered highly difficult. Countries with a legislative ELV system commonly set a target for recovery rates, with many aiming for more than 95 % recovery. In order to reach this target, higher efficiency in ASR recovery is needed, in addition to material recycling of collectable components and metals. Environmentally friendly design was considered necessary at the planning and manufacturing stages, and the development of recycling systems and techniques in line with these changes are required for sound ELV management.

[Purpose]Source-separated collection of food waste has been reported to reduce the amount of household waste in several cities including Kyoto, Japan. Food waste can be reduced by various activities including preventing edible food loss, draining moisture, and home composting. These activities have different potentials for greenhouse gas (GHG) reduction. Therefore, we conducted a life-cycle inventory analysis of household waste management scenarios for Kyoto with a special emphasis on food waste reduction activities. [Methods]The primary functional unit of our study was “annual management of household combustible waste in Kyoto, Japan.” Although some life-cycle assessment scenarios included food waste reduction measures, all of the scenarios had an identical secondary functional unit, “annual food ingestion (mass and composition) by the residents of Kyoto, Japan.” We analyzed a typical incineration scenario (Inc) and two anaerobic digestion (dry thermophilic facilities) scenarios involving either source-separated collection (SepBio) or nonseparated collection followed by mechanical sorting (MecBio). We assumed that the biogas from anaerobic digestion was used for power generation. In addition, to evaluate the effects of waste reduction combined with separate collection, three food waste reduction cases were considered in the SepBio scenario: (1) preventing loss of edible food (PrevLoss); (2) draining moisture contents (ReducDrain); and (3) home composting (ReducHcom). In these three cases, we assumed that the household waste was reduced by 5%. [Results and discussion]The GHG emissions from the Inc, MecBio, and SepBio scenarios were 123.3, 119.5, and 118.6 Gg CO2-eq/year, respectively. Compared with the SepBio scenario without food waste reduction, the PrevLoss and ReducDrain cases reduced the GHG emissions by 17.1 and 0.5 Gg CO2-eq/year. In contrast, the ReducHcom case increased the GHG emissions by 2.1 Gg CO2-eq/year. This is because the biogas power production decreased due to the reduction in food waste, while the electricity consumption increased in response to home composting. Sensitivity analyses revealed that a reduction of only 1% of the household waste by food loss prevention has the same GHG reduction effect as a 31-point increase (from 50% to 81%) in the food waste separation rate. [Conclusions]We found that prevention of food losses enhanced by separate collection led to a significant reduction in GHG emissions. These findings will be useful in future studies designed to develop strategies for further reductions in GHG emissions.